Refrigerants such as hydrochloroflurocarbons (HCFCs) and hydrofluorocarbons (HFCs) have been identified as having high global warming potential. Yet, their use has been ubiquitous in modern air-conditioning and refrigeration systems. With increasing concern over global warming and attendant government regulation, there is an increasing need to identify alternative technologies. Beyond identifying substitute refrigerants that can be employed in existing systems, solid-state materials have been considered as a potential solution, especially in view of their lack of global warming potential.
Existing refrigeration technologies employ a vapor compression cycle (VCC) that operates in a continuous manner. In contrast, existing solid-state cooling technologies, such as magnetocaloric, thermoelastic, and electrocaloric systems, operate in a cyclic manner. Moreover, solid-state cooling technologies may enjoy other advantages as compared to VCC technologies, such as reduced noise, lack of high pressure components, and lower maintenance cost.
However, solid-state cooling technologies have had limited market development to date due to a variety of disadvantages. In particular, solid-state cooling systems typically have less useful cooling power as compared to traditional VCC system due to parasitic internal latent heat losses. Such losses may be attributable to the sensible heat required to change the temperature of the refrigerant material between different levels during cyclic operation, for example, the heat sink and the heat source when operating as a heat pump. While both VCC and solid-state refrigeration systems may experience such parasitic losses, solid-state materials typically have much smaller latent heat available than VCC refrigerants.
Embodiments of the disclosed subject matter may address the above-mentioned problems and limitations, among other things.